Publicaciones: Sistemas Hibridos Nanoestructurados Archivos - Centro de Investigación en Nanomateriales y NanotecnologíaCentro de Investigación en Nanomateriales y Nanotecnología
Publicaciones: Sistemas Hibridos Nanoestructurados

Hello world! Please change me in Site Preferences -> This Category/Section -> Lower Description Bar

03

Aug 2018

Cycloidal Domains in the Magnetization Reversal Process of Ni80Fe20/Nd16Co84/Gd12Co88 Trilayers

Posted by / in Publicaciones Destacadas, Publicaciones: Sistemas Hibridos Nanoestructurados, Publications 2018, Publications Nanostructured Hybrid Systems 2018, Últimas Publicaciones CINN / No comments yet

The mag netization reversal of each individual layer in magnetic trilayers (permalloy/NdCo/GdCo) is investigated in detail with x-ray microscopy and micromagnetic calculations. Two sequential inversion mechanisms are identified. First, magnetic vortex-antivortex pairs move along the field direction while inverting the magnetization of magnetic stripes until they are pinned by defects. The vortex-antivortex displacements are reversible within a field interval which allows their controlled motion. Second, as the reversed magnetic field increases, cycloidal domains appear in the permalloy layer as a consequence of the dissociation of vortex-antivortex pairs due to pinning. The field range where magnetic vortices and antivortices are effectively guided by the stripe pattern is of the order of tens of mT for the NiFelayer, as estimated from the stability of cycloid domains in the sample.

Please select the social network you want to share this page with:

27

Jul 2018

3D reconstruction of magnetization from dichroic soft X-ray transmission tomography

Posted by / in Publicaciones: Sistemas Hibridos Nanoestructurados, Publications 2018, Publications Nanostructured Hybrid Systems 2018, Últimas Publicaciones CINN / No comments yet

The development of magnetic nanostructures for applications in spintronics requires methods capable of visualizing their magnetization. Soft X-ray magnetic imaging combined with circular magnetic dichroism allows nanostructures up to 100-300 nm in thickness to be probed with resolutions of 20-40 nm. Here a new iterative tomographic reconstruction method to extract the three-dimensional magnetization configuration from tomographic projections is presented. The vector field is reconstructed by using a modified algebraic reconstruction approach based on solving a set of linear equations in an iterative manner. The application of this method is illustrated with two examples (magnetic nano-disc and micro-square heterostructure) along with comparison of error in reconstructions, and convergence of the algorithm.

Please select the social network you want to share this page with:

09

Mar 2018

Determination of the out-of-plane anisotropy contributions (first and second anisotropy terms) in amorphous Nd-Co thin films by micromagnetic numerical simulations

Posted by / in Publicaciones: Sistemas Hibridos Nanoestructurados, Publications 2018, Publications Nanostructured Hybrid Systems 2018, Últimas Publicaciones CINN / No comments yet

Amorphous Nd-Co thin films exhibit stripe shaped periodic magnetic domains with local out-of-plane magnetization components due to their perpendicular magnetic anisotropy. This anisotropy has been quantified in a fairly simple way by reproducing the experimental magnetization curves by means of micromagnetic numerical simulations. The simulations show that the first (K1) and second (K2) anisotropy constants must be used to properly describe the variation of the stripe domains with the in plane applied magnetic field. A strong temperature dependence of both K1 and K2 has been obtained between 10 K and room temperature. This anisotropy behavior is characteristic of two magnetically coupled 3d-4f sublattices with competing anisotropies.